The present invention generally relates to devices for sealing the combustion chamber of a gas-fired appliance to prevent the incursion and possible ignition of flammable vapors. More specifically, the invention pertains to a device for allowing various components to extend through a combustion chamber vapor barrier without compromising the seal established by such barrier.
A potential hazard inherent in the operation of a gas-burning appliance is that it may cause flammable vapors to ignite that happen to collect in and around the appliance. Ignition may either be caused by the burner or pilot flame or by an electric or electronic ignitor upon being energized. This is especially problematic in for example water h eaters or furnaces that are located in garages in which cars are parked where the leakage or spillage of gasoline may occur. Once a combustible mixture reaches the appliance, a fire or an explosion may result.
Efforts to address this potential safety hazard have been previously directed toward ensuring adequate ventilation in and around the appliance, the elevation of the appliance to distance it from flammable vapors that are denser than air, and more recently, the isolation or sealing of the combustion chamber from its surroundings. This latter approach not only prevents the incursion of vapors into the combustion chamber but also prevents the propagation of flame therefrom.
A difficulty associated with effectively sealing the combustion chamber of a typical gas-burning appliance is inherent in the necessity for various conduits to extend into the combustion chamber from the exterior of the appliance. The fitment of a sheet metal enclosure about the entire combustion chamber is typically relied upon to form a vapor barrier. The extension of any conduit through such barrier requires that an appropriate opening be formed in the barrier and that any gap between the installed conduit and the surrounding barrier material be closed off. An additional requirement is inherent in the fact that such conduits may have to be removed to allow access to the interior of the combustion chamber or that such conduits will need servicing or replacement at some time during the service life of the appliance. This requires that any sealing device that is in place between the conduit and the vapor barrier must be capable of maintaining an effective seal yet should allow the ready removal of the conduit when it is desired to do so. The sealing device should also be reusable and easily re-installable. Additionally, the sealing device should not deteriorate during the service life of the appliance. Accordingly, it must be capable of withstanding the elevated temperatures it is routinely subjected to due to its proximity to flame and must additionally be able to withstand even higher temperatures as may be mandated by various regulating agencies with regard to fire safety. Finally, the sealing device should be inexpensive to manufacture.
A seal configuration that had previously been considered included a separate grommet and spring combination for each of the various conduits that were extended through the barrier. A spring that was relied upon to maintain each such grommet in place which rendered the installation process rather cumbersome.
A sealing mechanism is needed for use between a combustion chamber enclosure and conduits that extend there through that is capable of maintaining an effective seal, that readily enables the removal and replacement of conduits, that readily enables an effective seal to be reestablished upon reinstallation, that is readily configured to accommodate multiple conduits, that does not deteriorate during the service life of the associated appliance and that is inexpensive to manufacture.
The present invention provides a sealing mechanism for sealing gaps between a combustion chamber enclosure and conduits that are extended there through. More particularly, a grommet type component is provided which cooperates with a specially configured opening formed in the enclosure material. The device may be configured to accommodate one or more conduits and is repeatedly reusable. Upon insertion through the opening in the enclosure, the grommet component locks into place by a slight rotation thereof.
The opening that is formed in the enclosure material is configured to define a depressed rim from which two diametrically opposed tabs extend inwardly therefrom. The grommet component has distal end configuration that allows it to be inserted into the opening and past the tabs. A flange prevents over-insertion while grooves formed in the sides of the grommet component are precisely dimensioned to receive and grasp the tabs when the inserted grommet is rotated into place. Perforations formed in the grommet component are dimensioned so as to provide a snug fit with the specific conduits that are to be inserted there through. Perforations formed along the edges of the grommet are dimensioned such that a snug fit with a conduit is achieved by a cooperation of the grommet surface and adjacent rim surface.
The sealing device may be configured to accommodate a single conduit or to simultaneously accommodate multiple conduits such as for example a gas line that feeds fuel to the pilot light, thermocouple with which the existence of a pilot flame is monitored and the wiring for a piezo electric ignitor with which the pilot flame is ignited. These components must all necessarily extend through the vapor barrier enclosure to the burner as the controller valve from which they emanate is typically affixed to the exterior of the appliance.
The grommet component is preferably formed by the machining of powdered aluminum. Alternatively, powdered zinc or steel may be used. Die cast aluminum or zinc or machined aluminum or steel are also viable alternatives as is high temperature plastic molding.